How to Resolve 'org.hibernate.MappingException: Unknown Entity' in Hibernate 5?

org.hibernate.MappingException: Unknown Entity in Hibernate 5

Problem: An exception occurs with the message "org.hibernate.MappingException: Unknown entity" when attempting to integrate Hibernate 5.0 with MySQL.

Cause: This issue is encountered specifically with Hibernate 5.0.0 and 5.0.1 versions but not with Hibernate 4.3.9. The error stems from a discrepancy in how Hibernate 5 handles configuration compared to previous versions.

Solution: To resolve this issue, adjust the code responsible for creating the SessionFactory:

// Incorrect approach for Hibernate 5
Configuration configuration = new Configuration();
configuration.configure();

ServiceRegistry sr = new StandardServiceRegistryBuilder().applySettings(configuration.getProperties()).build();

SessionFactory sf = configuration.buildSessionFactory(sr);

Correct approach for Hibernate 5:

• Standard XML Configuration Files (hibernate.cfg.xml and hibernate.properties):

SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();

• Loading Properties from a non-standard file:

ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder().configure().loadProperties("hibernate-h2.properties").build();
SessionFactory sf = new Configuration().buildSessionFactory(serviceRegistry);

• Loading Properties from File Path:

File propertiesPath = new File("some_path");
ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder().configure().loadProperties(propertiesPath).build();
SessionFactory sf = new Configuration().buildSessionFactory(serviceRegistry);

The above is the detailed content of How to Resolve 'org.hibernate.MappingException: Unknown Entity' in Hibernate 5?. For more information, please follow other related articles on the PHP Chinese website!